Helicopter supported aerial fire suppressant applicator

ABSTRACT

A HELICOPTER-TRANSPORTED FIRE SUPPRESSION SYSTEM AND METHOD IS DESCRIBED WHEREIN A FIRE SUPPRESSION MEDIUM SUCH AS WATER, AQUEOUS FOAM, SLURRIES AND THE LIKE ARE ACCURATELY DIRECTED TO THE PRECISE LOCATION OF A FIRE OR TO A PORTION OF A FIRE TO BE TREATED BY PROJECTING A COHERENT STREAM OF THE FIRE SUPPRESSION MEDIUM OUTWARDLY FROM THE FIRE SUPPRESSION SYSTEM BY LOCATING A NOZZLE MEANS BEYOND THE EFFECTIVE AREA OF HELICOPTER ROTOR DOWNWASH TO AVOID INTERFERENCE WITH THE STREAM BY THE DOWNWASH.   THE HELICOPTER PILOT CONTROLS THE LOCATION AND DIRCTION OF APPLICATION OF THE FIRE SUPPRESSION MEDIUM BY CONTROLLING THE ALTITUDE, ATTITUDE AND LOCATION OF THE HELICOPTER AND CONTROLS THE QUANTITY AND COMPOSITION OF FIRE SUPPRESSION MEDIUM BY ACTUATING PUMPING MEANS THEREFORE FROM THE PILOTS CONTROL STATION.

L. L. MATTSON Feb. 6, 1973 HELICOPTR SUPPORTED AERIAL FIRE SUPPRESSANTAPPLICATOR Filed May 17, 1971 United States Patent O 3,714,987 HELICPTERSUPPORTED AERIAL FIRE SUPPRESSANT APPLICATOR Larry L. Mattscn, 3624164th Place SE., Bellevue, Wash. 98008 Filed May 17, 1971, Ser. No.143,995 Int. Cl. A62c 3/02; E6441 1/16; BOSb 17/02 U.S. Cl. 169-2 A 6Claims ABSTRACT GF THE DISCLOSURE A helicopter-transported firesuppression system and method is described wherein a fire suppressionmedium such as water, aqueous foam, slurries and the like are accuratelydirected to the precise location of a fire or to a portion of a fire tobe treated by projecting a coherent stream of the fire suppressionmedium outwardly from the fire suppression system by locating a nozzlemeans beyond the effective area of helicopter rotor downwash to avoidinterference with the stream 'by the downwash. The helicopter pilotcontrols the location and direction of application of the firesuppression medium by controlling the altitude, attitude and location ofthe helicopter and controls the quantity and composition of firesuppression medium lby actuating pumping means therefore from the pilotscontrol station.

BACKGROUND OF THE INVENTION This invention relates to apparatus and amethod for preparing and applying fire suppressant and retardantmaterials to fires from an aerial platform. This invention furtherrelates to an apparatus for and a method of preparing and applying fireretardant materials accurately upon a desired specific location from ahelicopter hovering adjacent the fire. This invention specificallyrelates to apparatus for a technique of aerial fire fighting of forestfires in remote areas by means of direct application of a stream of firesuppressant or retardant materials to the precise area of the firechosen by the pilot of a helicopter carrying the fire fightingapparatus.

Suppression of fires in wilderness areas heretofore has been largelyconducted by ground crews dispatched for that purpose from a centralfire control station to travel by foot, by aircraft or by helicopter tothe site of the fire in the event that the fire is not immediatelyadjacent an access road. In remote areas, fire fighting crews arelimited to the tools which they have carried with them or which aresubsequently dropped to the scene from aircraft. Combating fires in thismanner is a time consuming, laborous and extremely inefficientprocedure. Such fire fighting techniques have been augmented andenhanced by the use of aerial bombardment techniques in which a fireretardant material such as water or slurries of retardant materials inwater are dropped upon the fire site from low-flying aircraft. Suchactivites tend to 'both cool the fire and retard its progress throughlow Vegetation and trees treated by the aerial drop.

Helicopters have also been used for fire suppression activities byspraying the retardant material into the downwash from the rotors of thehelicopter, causing a distribution of liquid droplets and particles offire suppressant or retardant materials upon an area limited to theground surface impinged upon by the downwash from 3,714,987 PatentedFeb. 6, 1973 the helicopter rotor. This type of application of firesuppressant materials is extremely inefiicient in that sufficientdensity and volurne of fire suppressant media is lacking to adequatelycover and suppress a fire, and such materials are not specificallyapplied to the area at which the fire suppressant material is mosturgently needed. Rather, a general distribution of the fire suppressantmaterial occurs over a broad area beneath the helicopter. Such a Widedistribution is helpful in certain types of fires in which a large areais affected by the fires, however, in the event that fires havebroadened into a long line of fire front, such as is found in thegeneral nature of forest fires, there is a great need for the ability toapply the fire suppressant or retardant materials to a specific areaWith a great deal of control and accuracy.

OBJECTS OF THE INVENTION It is accordingly an object of this inventionto provide a means of delivery and a method by which fire suppressantmaterial may be delivered to a specified and closely confined area froman aerial platform.

It is a further object of this invention to provide ahelicopter-supported fire suppression means and method of use thereofuseful in applying a stream of fire retardant or suppressant materialsdirectly upon a point remote from the helicopter.

It is a still further object of this invention to provide apparatus forfire fighting purposes which is supportable and transportable by ahelicopter and which may be easily jettisoned upon pilot command in theevent of a helicopter power failure.

One specific object of this invention is to provide a method forcombating forest fires in remote areas and the apparatus necessary forsuch Operations which may be transported by a helicopter and may berefilled at any location in which there is water accessible to ahovering helicopter.

It is a further specific object of this invention to provide tank fillermeans suitable for use with a helicoptermounted fire fighting apparatusconstructed and arranged so that the tank may be rapidly filled from anysource of water accessible to a hoverng helicopter without therequirement of landing the helicopter during the tank filling operation.

An additional specific object of this invention is to providehelicopter-mounted fire fighting apparatus in which the jet nozzle forapplying the fire suppressant or retardant material extends beyond thedownwash of the helicopter rotor so that no interference with thecontinuity and integrity of the stream projected from the nozzle isencountered from the downwash to ensure the maximum density andcontrollability of the stream of fire suppressant medium, making it lesssusceptible to the high winds encountered during certain firesituations.

SUMMARY OF THE INVENTION In accordance with the present invention, arefillable tank is mounted on the fuselage of a helicopter by means ofthe widely used cargo hook or other suitable types of connection. Thetank is provided with an efiicient lightweight pumping system which willprovide a positive high pressure flow of Water through an in-lineinductor system for mixing a foam precursor material or wetting agenttherein to a suitable nozzle at the end of a length of pipe extendingbeyond the area affected by the downwash from the rotor blades. Thenozzle of the pipe extending beyond the downwash from the rotors isadapted to project a coherent stream of fire retardant or suppressantmaterials, unaffected by the rotor downwash, outwardly from thehelicopter-mounted tank system to a point within the range ofobservation of the pilot of the helicopter. The externally mounted tankis of a readily refillable nature, permitting the helicopter pilot torefill the tank from any body of Water having a sufiicient depth tosnbstantially receive the depth of the tank. The tank is fitted with atleast one large ball-seat type valve assembly which will unseat as thehydrostatic pressure is increased upon the lower side as a result of thetanks being lowered into the water while the helicopter is hoveringimmediately above the water's surface. The ball valves are adapted toclose immediately upon removal of the tank from the water due to theforces applied thereto by hydrostatic pressure to seat the balls upontheir respective valve seats.

This means of employing fire suppressant or retardant materials to afire utilizes to its full extent the maneuverability and adaptability ofthe helicopter to fire fighting situations in that when airborne thepilot controls the stream of fire suppressant or retardant materials bymaneuvering the altitude, attitude and direction of the helicopter topoint the nozzle of the fire suppression apparatus in the desireddirection to inundate the base of the fire With suppressant or retardantmaterials. The pilot controls the direction at which the firesuppressant or retardant materials is projected from his vehicle bychanging the location of the entire helicopter and through actuation ofa simple on-off switch controlling the fiow of fire suppressant orretardant materials.

The method by which this invention is used comprises initially fillingthe chemical retardant and suppressant material supply tank or tankswith appropriate foam precursors, wetting agents and the like andfilling the large tank positioned beneath the helicopter. The helicopterpilot, upon receiving notification of a fire would then proceed to thescene of a fire and upon arrival commence application of the appropriatefire suppression or retardant medium. Frequently the following procedurewould be utilized. First a foam material, formed by educting foamprecursor into the eductor would be projected outwardly through thenozzle onto the fire area to substantially blanket the fire and deprivethe fire of the oxygen necessary for combustion. The foam would also actto cool the situs of the fire. With this important first step achieved,the helicopter pilot may then switch to a water application mode, withor without wetting agents.

The system and method provided in this invention isolates the firecombating system completely from the helicopters Operating andmaneuvering system. Each lfire suppression unit is self-contained inthata complete tank, pumping apparatus, battery, extension pipe andnozzle are provided independently of the helicopter and are connectedonly by cargo hooks widely utilized in helicopter Operations and lightcontrol Wire and hydraulic connections to chemical tanks containedwithin the helicopter cargo space. The pilot will thus be able tojettison the great majority of his load of fire suppression equipment inthe event of helicopter engine failure, giving him the added controlthat a light helicopter has during hovering situations. In addition,external connection of the fire fighting unit permits the load to beclassified as an external load which under existing Federal AviationAdministration regulations permits a larger load to be carried.

These and other objects, advantages and attributes of this inventionwill become more readily apparent through a detailed examnation andevaluation of the following description of the preferred embodimentstaken in conjunction With the appended drawings.

4 IN THE 4D-RAWINGS PIG. l shows a helicopter equipped with the firefighting apparatus discussed herein shown dispensing fire suppressant orretardant material upon a fire site.

FIG. 2 shows a cross sectional view of the tank mechanism and associatedmounting apparatus for the fire suppression unit of this invention.

FIG. 3 shows a schematic representation of the fluid fiow system used incarrying out the method of this invention and showing schematically thecontrol system utilized.

FIG. 4 shows the details of a releasable boom fastening means.

FIG. 5 shows a schematic representation of the fire suppression systemof this invention.

Referring more particularly to the drawings wherein like numeralsindicate like parts, there is seen in FIG. 1 a side elevation of ahelicopter carrying the fire fighting apparatus of this invention. Thehelicopter shown generally at 201 having a rotor 22 and a stabilizerpropellcr 24. The helicopter 20 is shown as one of the high capacitystyles of helicopter presently manufactured which is adapted to carrysubstantial weight loads. The helicopter 20 is shown with the firesuppressant applicator system of this invention strapped beneath thecraft With the nozzle 30 extending beyond the downwash area from rotors22. The fire suppressant applicator system shown in PIG. 1 includes awater tank 32, a pump 35 and an eductor-type mixer 3'6. Conduit 38extends outwardly from the tank 32 and is adapted to carry the Water orwater and chemicals mixture to nozzle 30' which may then be projectedoutwardly from the nozzle 30 to the fire. The nozzle is positionedbeyond the rotor downwash and is so located that the pilot of thehelicopter 20 may observe the stream 31 of the fireV suppressant orretardant material being projected outwardly from nozzle 30.

In FIG. 2 the details of the tank construction and the mounting meansutilized in strapping the tank to the bottom of the helicopter is shownin the cross-sectional view. The tank system is connected to thehelicopter by means of cargo hook 42, which engages the swivel 44positioned directly above the center of the tank 32. The swivel 44 inturn engages a bolt member 46, which projects downwardly through thetank and is threadingly engaged by nut 48 to attach the tank 32 to thehelicopter cargo hook 42. The upstanding portion of swivel 44 is hookedby the cargo hook and the bolt 46 is run up tight by the rotation of nut48 so that the tank fits snugly against the bottom side of thehelicopter. A foam ru'bber pad 56 is positioned in the tank 32 and thebottom 58 of the helicopter 20 such that a firm yet resilient engagementresults between the tank 32 and the helicopter 20. The foam rubber pad'56 contains an interior aperture 57 through which passes the cargo hookengaging swivel 44 and the chemical line 40. The chemical tank 34 ispositioned inside the fuselage of the helicopter 20 and is connected tothe suction side of the eductor 36 by means of condluit 40. A quickdetaching connector 60 is utilized to permit rapid jettison of the tankin the event of helicopter motor failure. The in-line eductor mixer 36is shown positioned out the outlet of the pump-motor unit 35 and servesto thoroughly mix chemicals such as foam precursors, wetting agents andthe like with water to form the desired fire suppression or retardantsubstance.

Internal support straps 54 are utilized to provide the necessarystrength and rigidity to the tank. At the bottom of tank 32 are a pairof water inlet ports 52, which are utilized to fill the tank from aconvenient source of water such as a lake or a stream. The valvemechanism is a ball and seat arrangement in which ball 48 is free totravel up and down confined by Vertical restraining elements 47 inresponse to hydrostatic pressures, upward movement of the ballsresulting in opening of the valve mechanism whenever the tank is partlyor completely submerged and downward movement to close the valvemechanism whenever the tank is removed from the water thus preventingflow of water from the tank. The pump-motor unit 35, shown in FIG. 2,draws water from the lowermost portion 54 of tank 32 through inlet pipe33, and discharges the water into an eductor-mixer 36. A water proximitysensor 60 is shown in position on the bottom end of threaded member 46to aid the pilot in determining the location of the tank with respect tothe location of the body of water from which the tank is to be filled.

In FIG. 3 the details of the ball and seat valve shown in FIG. 2 arepresented in a perspective view. Ball 48 is permitted to travel up anddown within the confines of Vertical restraining elements 47 and isadapted to seat upon valve seat 47 and form a seal whenever thehydrostatic pressure is suflicient to force the ball down against seat47. The spherical ball 48 is preferably a density equal to or slightlyexceeding the density of water so that hydrostatic forces will cause theball to unseat, whenever the tank is submerged, but will not cause theball 48 to float in a partially or completely filled tank.

In FIG. 4 the details of one embodiment of a releasable boom fasteningmeans are shown. Strut 62 extends outwardly from the fore portion ofskid 26 and carries a boom-engaging clip member 60 which is adapted tobe released easily in the event of tank jettison.

In FIG. 5 a schematic representation of the fire suppression system ofthis invention is shown. The chemical tanks 34a and 34h contain foamprecursor, wetting agent or other suitable fire suppression or retardantagents suitable for use with an aqueous system. The water tank 32contains a suflicient amount of water to extinguish a reasonably largesized blaze, yet is within the carrying capabilities of a helicopter.The water tank 32 contains therein the water pump and motor unit 35, asshown in position on the top side of tank 32, and is driven byelectrical power supplied by battery 70. The pump-motor unit 35 iscontrolled by a switch mechanism 74 accessible to the helicopter pilot.Water under pressure is supplied by the motor-pump unit 35 to theeductor mixer 36 wherein chemicals from tank 34a or 34b are thoroughlymixed and projected outwardly from nozzle 30 at the tip of boom 38 asthe fire suppressant or retardant material. In the alternative, wateralone may be sprayed out through nozzle 30 to soak a fire area after thefoam retardant has been used to suppress and partially cool the blaze,The proper chemical material for forming the fire suppressant orretardant material may be chosen from tank 34a or 34h, or chemicaltreatment may be omitted by p-roper setting of valve 76. The method ofusing the apparatus shown in detail in the attached drawings includesthe following steps.

The chemical storage tanks 34a and 34h are filled with the propermaterial for use with water to form the desired fire suppressant orretardant medium. Water tank 32 is filled and the apparatus which haspreviously been attached to the helicopter 20 is then ready for use.

Upon receiving notification of a fire, the helicopter pilot wouldimmediately proceed to the scene of the fire and commence suppressionactivities. Initially, the helicopter pilot would apply a foam materialto the fire site to knock down the fire and deprive the fire of theoxygen necessary for combustion. 'In addition, the presence of aqueousfoam material Will substantially cool the fire and impede its progress.

The helicopter pilot would then switch his mode of operation into awater application phase in which water from tank 32 is utilized byitself or in conjunction with a 'wetting agent from tank 34b tothoroughly inundate and extinguish the fire.

For fires in areas inaccessible to the usual firefighting equipment thisinvention can be utilized to a great ad- Vantage in knocking down thefire and building a barrier across which the fire cannot travel. Thistype of usage of this invention involves the construction of a fire lineutilizing aqueous foam material. This is accomplished by positioning thehelicopter at a location in which tube 38 is substantially perpendicularto the edge or front of the fire. Foam material is then directed uponthe edge of the fire such that a strip of one or more feet in width isinundated with the foam material and the fire substantially extinguishedat that location, by the presence of the foam. By utilizing a ratherpersistent foam, the progress of the fire will be impeded and othertechniques including substantially completely soaking the fire area withwater from the helicopter-supported firefighting system may be utilizedto completely extinguish the fire.

While only preferred embodiments of the methods and apparatus of thisinvention, together with various modifications thereof have beendeseribed in detail herein and shown in the accompanying drawings, itwill be evident that various further modifications are within thecapability of those skilled in the art without departing from the scopeof the invention.

I claim as my invention:

1. An airborne fire suppression system for depositing a fire suppressantor retardant material on a closely controllable location comprising:

a liquid storage tank having means thereon to releasably engage asupport mechanism on the bottom side of a helicopter said tank to bepositioned directly beneath said helicopter;

a boom means extending outwardly from the forward portion of said tank,said boom of suflicient length to position a nozzle beyond the downwashpattern of said helicopter so that liquids ejected from said nozzle areprojected outwardly from said nozzle in a coherent stream;

means to supply liquid from said tank to said nozzle;

and,

means positioned at the bottom of said tank for rapidly filling saidtank from a body of water comprising valve means operable in response tohydrostatic pressure to fill said tank when said tank is submerged intosaid body of water and to prevent fiow of water from said tank said fillmechanism upon removal from said tank from said body of water.

2. The apparatus of claim 1 wherein a substance is added to the liquidcontained in said tank prior to supplying said liquid to said nozzle toenhance the fire suppression characteristics thereof.

3. The apparatus of claim 2 wherein said chemical material is added tosaid liquid by means of an eductormixer means operated by the fiow ofliquid to said nozzle.

4. The method of combatting a fire from an aireraft having a downwardpattern and having the capability to hover adjacent the fire comprisingthe steps of:

extending a boom from the aireraft beyond the influence of said downwardpattern, said boom having a nozzle at the tip thereof adapted to form arelatively coherent stream of liquid projecting outwardly therefrom;

supplying a fire retardant or suppressant liquid under suflicientpressure to said boom to force said liquid out of said nozzle in acoherent stream; and

directing said coherent stream upon said fire by controlling theposition of said aireraft.

5. The method of claim 4 and the step of filling a water tank means usedto supply said fire retardant or suppressant liquid to said nozzle byimmersing of said tank I means through filling means operable byimmersion of said tank, said tank releasably positioned beneath saidhelicopter so that said filling step is accomplished while saidhelicopter hovers over a body of water with said tank at least partlyimmersed therein.

6. An airborne fire suppression system for depositing a fire suppressantor retardant material on a closely controllable location comprising:

a liquid storage tank having means thereon to releas-ably engage asupport mechanism on the bottom side of a helicopter said tank to bepositioned directly beneath said helicopter;

a boom means extending outwardly from the forward 7 8 -portion of saidtank, said boom of suflicient length 2,461,304 2/1949 Wilson 137-533.13X to position a nozzle beyond the downwash pattern 2,611,439' 9/1952Faulkner 169-15 of said helicopter so that liquids ejected from Said2,934,149 4/1960 Bedford et al. 169-15 nozzle are projeeted outwardlyfrom said nozzle in 3,234,962 2/1966 Williamson 169-13 X a coherentstream; 5 3,442,334 5/ 1969 Gousetis 169 2 R means to supply liquid fromsaid tank to said nozzle; 3,485,302 12/1969' Thorpe 169-2 R and, 1 d k fdl fin d 3,580,339 5/1971 Nance 169-2 A water in et means on sai tan orra i in sai vtank with water. p y g FOREIGN PATENTS 773,893 12/1967Canada 169-2 R References Cited 10 UNITED STATES PATENTS 3,s19,o807/1970 Rochat 169 2R U.s. C1. x.R. 3,494,423 2/1970 Stansbury et al169-2 R 3,603,340 9'/1971 Rousselet 137-533.13 X 15 16945, 137 533'13ROBERT S. WARD, JR., Primary Exa'miner

